The kid in question is 7 years old and just finishing first grade. His parental guardian is his aunt (his father is not in the picture and his biological mother lost custody of him when he was very young). He has lived with his aunt for most of his life and calls her "mom". She also has a biological son who is also still a minor, he is around 12 or 13 and is in seventh grade. His aunt is not a bad parent, but she does not read to him (she is also not a native English speaker) or really spend time playing with him. He was also not spoken to very much as a kid, and as part of that his speech development is a little behind (he is still perfectly understandable, but I would say as a non-expert that his verbal skills are a couple of years behind what I would expect). He was enrolled in school late and for his first year and a half attended underfunded schools but now attends a much more well-funded school.
He does not have any specific intellectual or learning disability and while he is not brilliant he is of typical ability and I don't think that he has specific learning challenges. He can get easily frustrated sometimes when he is trying to do something that he doesn't understand (for example, if I try to get him to sound out words that he is having trouble with he will try for a bit and then give up and ask me to just read it). This is not insurmountable, as he does not act destructively or completely refuse to continue, although it can take some coaxing and determination to have him continue, and I will often just tell him the words and have him continue to sound out a couple of pages later. He is a good natured kid who gets along well with other kids his age. His brother/cousin that he lives with has a lot of anger and the dynamic there is not great (he worships the brother/cousin and the brother/cousin sometimes hangs out with him but also can be a bully).
He has made significant progress in reading and writing in the last half of a year (going from basically just knowing his ABCs to being able to recognize some sounds and read some words). However, he continues to be behind in his classes and because reading is such a fundamental skill, it is important that he gets up to grade level!
I am his brother's girlfriend (there is a huge age gap). His brother (27) and sister (25) both love him very much and try to support him as much as possible, but neither of them are in a position to take custody of him or anything like that. His sister will be starting law school soon and lives in another state, although she tries to facetime him often and support him while she can. His brother (my significant other (SO)) lives near him and sees him multiple times a week. However, he is going to be going to finish his last year of undergrad in another state starting this fall (he took a year off). I see him almost as often as my SO does and he likes me and enjoys hanging out with me. We are teaching him how to bike right now so we typically go out biking with him for at least 30 minutes. My SO helps him with his math (he is not as far behind in his math as his reading). I am the one who reads to him the most (I don't mind), largely because he vocally likes the way I read more.
My question is about both active and passive ways to get him up to grade level. He is starting summer in just a couple of days, and the time is a good chance to help catch him up and also keep his skills from eroding. We are trying to get him to make good friends in the neighborhood so that he can have fun with other kids his age as well as stay out of the house and away from the influence of his cousin/brother. We also try to play with him while he is around. When my SO goes back to school, I am going to hang out with him once or twice a week (his aunt has no problem with me taking him out). One of the big issues, however, is that we are not there most of the time and he has an iPad that his aunt essentially doesn't regulate his time on. It is frankly not possible to get her to supervise him most of the time or to read to him, so we need a passive way to get him learning. I am looking for suggestions or advice for ways to get him to learn without us necessarily being there - any possible ideas or suggestions would be greatly appreciated!